Research reveals sowing options for northern and central canola growers

Posted onFebruary 21, 2019

Plots of canola at West Dale in July 2018, where the Department of Primary Industries and Regional Development undertook a time of sowing trial to evaluate the merits of very early sowing on yield and quality.

Canola growers in the northern and central agricultural regions are set to benefit from the outcomes of recent time of sowing and variety selection research, which have revealed more flexible options for growers.

The WA Department of Primary Industries and Regional Development’s research will be profiled at the upcoming Grains Research and Development Corporation (GRDC) Grains Research Update in Perth.

Research officer Martin Harries said the research, with GRDC co-investment, identified a number of varieties with good yield stability across a range of sowing dates, which would help reduce the risk of dry sowing and the need to purchase multiple maturity types.

Mr Harries said while there had been interest in dry sowing very early canola, field trials found that bringing the sowing window forward to March 2019 and early April 2019 was a risky option in the northern region.

“Establishing canola in early autumn proved to be difficult in this region, due to the impact of hot, drying soil conditions and the need to sow canola shallow, due to its small seed size,” he said.

Mr Harries said the research also showed sowing canola varieties with a wide flowering window at dates later than normal generated more encouraging results, however, there were large differences between the 11 varieties trialled.

“The responses from the triazine tolerant hybrid varieties were well above what would be expected from later sowing dates, with plots sown on 17 May (2019) at Tenindewa, west of Mullewa, yielding 1.6 tonnes per hectare overall,” he said.

“The highest yielding varieties at Tenindewa produced around 0.8t/ha when sown very late on 20 June (2019).

“These new short season hybrids flowered early and put on substantial bulk and were flexible enough to keep flowering while the season was favourable, which gave the yield response.

“The introduction of these plant types may provide growers with an option to reduce the risk of late sowing or late emergence from dry sowing in this environment.

“In the central region trials at Wongan Hills and West Dale, south of Beverley, mid-season varieties had the most flexibility in their plant development and flowering duration.”

Mr Harries said the analysis at these sites suggested mid-season varieties could provide a flexible option for growers, providing the opportunity to pre-order seed suitable for a reasonably wide sowing window.

“This is becoming more important, as more canola is being dry sown and the establishment date at the break of the season can be unpredictable,” he said.

The research outcomes were reinforced by Agricultural Production Systems sIMulator (APSIM) modelling, which simulates flowering dates and yields across locations and sowing dates.

Research officer Imma Farre said the modelled flowering dates compared reasonably well to the observed data from the mid-May 2019 sowing trials.

“The APSIM-Canola model was used to obtain the optimum sowing window where maximum canola yields would be achieved on average for different season length varieties and locations, keeping in mind the actual season is rarely similar to the average year,” Dr Farre said.

“While the APSIM-canola model has been validated for WA for the traditional sowing window and for older varieties, further model validation is required to extend the use of the model to very early sowings and new varieties.”

Mr Harries said the research would be replicated and extended in 2019 to include field trials at Esperance, to determine whether the findings could be extended to the southern region.

“We also intend to include lupins at all the field sites to evaluate whether sowing this crop deeper gives better establishment than canola in hot conditions and if the crop is a safer bet in taking advantage of March and early April rainfall,” he said.

The 2019 GRDC Grains Research Update will be held in Perth on Monday 25 and Tuesday 26 February 2019, while Regional Updates are scheduled for Albany and Geraldton.